The earthworking machinery industry has for years experienced the challenge of designing ground engaging tools (GET's) that not only have a combination of abrasion resistance, long wear life and impact resistance, but also the ability to retain their original shape and dimensions even after repeated use. The shape of a GET component, such as a bucket tip, is defined by several surfaces that are geometrically related to each other. This designed geometrical relationship of a GET component affects the earthmoving efficiency, such as the ability to penetrate soil and/or rocks, of the GET component. As a GET component penetrates soil and/or rocks, it begins to wear at locations where the normal forces acting upon the GET component by the soil and the resultant frictional stresses, are the highest. With the passage of time, the surfaces of the GET component become abraded in a non-uniform manner and the geometrical relationship of the various surfaces with respect to one another is altered. This alteration of the GET component's shape detrimentally affects its performance.
In the past, increased wear resistance has been achieved by increasing the hardness of the wear component of the GET component while high impact strength has been attained by increasing the fracture toughness of the wear component. It is known in the industry that the useful life of a GET component is related not only to the wear and impact resistance properties of its cutting edge or cutting bit, but is also related to the retention of dimensional relationship between the various facets of the GET component.
In the past, researchers at Caterpillar Inc., the assignee of the present invention, have developed composite materials having a combination of impact and wear resisting surfaces. Other methods developed at Caterpillar Inc. include techniques where abrasion resistant materials are welded onto a surface of, or into cavities in, the metal base comprising the GET component. Although the foregoing techniques have been very successful, there is a desire to continuously improve the ability of the GET component to retain its dimensional characteristics and thus retain its earthworking efficiency.
It has thus been desirable to have GET components having wear resistant materials that impart a combination of (i) wear and impact resistance properties, and (ii) properties that enable the GET component to retain its dimensional characteristics even at those locations on the tool which are exposed to most severe impact and abrasion forces.
The present invention is directed to overcome one or more problems of heretofore utilized GET components for the earthworking machinery industry.